Process for improving the magnetic qualities of iron-silicon-manganese-aluminium alloys.



ROBERT ABBOTT HADFIELD, OF SHEFFIELD, ENGLAND.

PROCESS FOR IMPROVING THE MAGNETIC QUALITIES 0F IRON-SILICON MANGANESE- ALUMINIUM ALLOYS.

Specification of Letters Patent.

Patented Feb. 10, 1914.

No Drawing. Application filed March 21, 1907, Serial-No. 363,664. Renewed June 27, 1913. Serial No.

T 0 all whom it may concern Be it known that I, ROBERT A. HADFIELD, a subject of the King of Great Britain and Ireland, residing at Parkhead, Sheflield, England, have invented a certain new and useful Improvement in Processes for Improving the Magnetic Qualities of. Iron- Silicon-Manganese Aluminium Alloys, of which the following is a specification.

.In U. S. Letters Patent. No. 745,829, granted to me December 1, 1903, I have described and claimed a process of producing a magnetic material of high permeability and low hysteresis action which consists in alloying a magnetic body with silicon, heating the alloy to a relatively high temperature below its melting point, allowing the alloy to cool, reheating it to a temperature below-that first employed and allowing to cool slowly. w

In U. S. Letters Patent No. 842,403, dated January 29, 1907 I have described an alloy containing iron, silicon, manganese fand aluminium in the following proportions, to wit: silicon from 2 to 4.5%, manganese not exceeding .7 and aluminium not exceed ing 1.3 o.

My present invention is a process of increasing the permeability and electric resistance, and decreasing the hysteresis action of the said iron-silicon-manganese-aluminium alloy. I carry my said process into efi'ect by melting together the ingredients in a suitable vessel, casting into ingots, rolling or working and treating the same by first heating the alloy to between 900 and 1100 centigrade, then allowing it to cool, then reheating to between 700 and 850 centigrade, that is, to a temperature lower than the one attained during the first heating and finally allowing the alloy to cool-slowly.

I claim: 1. The herein described process of obtaining an iron silicon manganese aluminium alloy of high magnetic permeability and electric resistance and low hysteresis action which consists in heating said alloy to a high temperature above 900 C. but below its melting point, allowing the alloy to coolslowly, reheating the alloy to a second high temperature but below about 850 C. and then allowing it to cool slowly.

ceeding about/7% and aluminium not exceeding about 1.3% then heating said alloy to a temperature ranging from about 900 C. to below 1100 C. then allowing the alloy 2. The process of producing a magnetic to cool, then reheating the alloy from a temperature ranging from about 700 C. to not over 800 C. and then finally cooling.

3. The herein described process of producing a magnetic alloy of high permeability and low hysteresis action which consists v in alloying iron with silicon from about 2.

to about 4.5%, manganese not, exceeding about .7 and aluminium not exceeding about 1.3%, then heating said alloy to a high temperature above about 900 C. but below its melting point, then allowing the alloy to cool slowly, then reheating the alloy to a high temperature not substantially above 850 C. and finally allowing it to cool slowly.

4. The herein described process of producing a magnetic alloy of high permeability and low hysteresis action which consists in alloying iron with silicon above about 2%, manganese not above about .7 and aluminium not above about 1.3%, then heating the alloy to above about 900 (1, then cooling, then reheating the alloy to below about 850 C. and finally cooling.

5. The herein described process of producing a magnetic alloy of high permeability and low hysteresis action which consists in alloying iron with silicon above about 2%, manganese not above about .7% and aluminium not above about 1.3%, then heat-.

ing the alloy to above about 900 0., then cooling slowly, then reheating the alloy to below about 850 C. and finally cooling slowly. i

In testimony whereof I have aflixed my signature in presence of two witnesses.

ROBERT ABBOTT HADFIELD.

Witnesses I HUGH HUGHES, WM. BROWN. 

